Partially annotate V8 for MemorySanitizer.

Partially annotate V8 for MemorySanitizer.

This is a part of https://codereview.chromium.org/26006004/.
These changes are enough to run most apps that embed V8 (by additionally
ignoring all memory accesses from V8), but don't help testing V8 itself in any
way.

R=danno@chromium.org

Committed: http://code.google.com/p/v8/source/detail?r=17331

[Evgeniy Stepanov, 2013-10-21 07:58:52]

ping

[danno, 2013-10-21 09:31:34]

This looks OK fundamentally, but one question: this only works with the ARM
simulator, right?

[Evgeniy Stepanov, 2013-10-21 09:59:33]

On 2013/10/21 09:31:34, danno wrote:
> This looks OK fundamentally, but one question: this only works with the ARM
> simulator, right?

This works in normal x86_64 build if we additionally ignore all memory accesses
from v8/src/* with a compile-time blacklist option. We still need to unpoison V8
heap because there are accesses to that memory from the embedding code via V8
headers.

I think we would not need any annotations at all with ARM simulator, if it
worked on x86_64. Unfortunately, MSan does not support 32-bit x86.

[danno, 2013-10-21 11:43:34]

lgtm

[Evgeniy Stepanov, 2013-10-21 12:29:14]

On 2013/10/21 11:43:34, danno wrote:
> lgtm

Thanks. This commit checkbox does not seem to do anything, and I don't have
commit rights to V8. Could you help me land this change please?

[danno, 2013-10-23 08:39:21]

Committed patchset #1 manually as r17331 (presubmit successful).